STUCK IN PHYSICSAll simulationsBuild a circuit. Follow the energy.
Choose components, route wires between their terminals and measure what happens. Explore series and parallel circuits, real cells, potential dividers and sensors—all on one workbench.
Use Wire to start at a terminal, click blank space to guide the route, then finish at another terminal. Wires avoid component bodies. Crossings are not electrical junctions unless they share a terminal. Use Move / select to select or redraw a wire. Escape cancels a connection; Delete removes the selected item. On a small screen, scroll the workbench sideways.
Component measurements
| Component | Current | Potential difference | Power absorbed (+) or supplied (−) at terminals |
|---|
A dash means the voltage is undefined or the ideal circuit has no unique solution, not a measured zero.
Place the meters correctly
Put an ammeter in series with the branch you want to measure. Put a voltmeter in parallel across the two points whose potential difference you want.
Ammeter: ideal zero resistance. Voltmeter: ideal infinite resistance. A misplaced ammeter can short a component or an ideal cell. The lab reports an undefined result when an ideal circuit is inconsistent or has no unique branch current.
In series, components share a branch current. In parallel, branches share the potential difference between their common junctions. Try extra ammeters in different branches and multiple voltmeters across different components.
Internal resistance and sensor dividers
A cell’s emf is energy supplied per unit charge. When it delivers current, internal resistance reduces its terminal potential difference and produces internal heating.
For an unloaded two-resistor divider, Vout across the lower resistor depends on its share of the total resistance. A lower-arm LDR or NTC thermistor changes the output as light or temperature changes. Adding a resistive load across the output changes the divider ratio; the workbench solves that loaded circuit too.
Model: steady DC, ideal wires and meters, ohmic resistors, and a cell represented by emf in series with internal resistance. Sensor curves are illustrative: LDR reference resistance is specified at 100 lx; NTC reference resistance is at 25 °C. No transients, self-heating, component ratings or non-ohmic lamp/diode behaviour are modelled.
Explore current electricity
Build series and parallel circuits with cells, resistors, switches and multiple meters. Route wires, rotate components and investigate internal resistance, loaded potential dividers and light or temperature sensors.
Supports current electricity topics in IB Physics and A Level Physics, with relevant circuit practice for AP Physics 2 and AP Physics C: Electricity and Magnetism.